The present invention relates to a management method, a system, and a management apparatus of a radio communication system, and further a program for its operational control, and more particularly to a control management technique of a load situation in a wireless LAN (Local Area Network) including a plurality of wireless base stations.
In a wireless LAN system that is comprised of a plurality of wireless LAN access points (AP), there has been conventionally known a load balancing control of avoiding a situation where communication loads are concentrated in a specific AP to enhance communication performance of the entirety of the system. A traffic amount that one AP can accommodate is limited, so in a case where an excessive load was applied to one AP, the communication performance (a throughput characteristic and a delay characteristic) declines in terminals connected to the above AP. So as to avoid it, in a patent document 1 was described the control technique in which each AP grasped the number of the terminals connected to its own AP and gave the terminals under connection an instruction for making a changeover of the connection to other AP in a case where the number of the terminals connected to its own AP was more than a pre-set connectable terminal number, thereby to carry out the load distribution.
In the technology of this patent document 1 (JP-P2002-185458A), the control was taken by monitoring operational information in real time, assuming that the traffic amount (load) that each terminal transmits/receives was equal. That is, assuming that in a case where the number of the terminals connected to one AP is equal to or more than the specified terminal number, the traffic beyond the processing ability of the above AP could occurs, a control of restricting the number of the connectable terminals is taken so that an overload situation can be avoided beforehand.
Also, a reference to a patent document 2 (JP-P1996-289366A) was made, in which a technology was disclosed of, in a mobile communication system having a plurality of wireless base stations connected to a switchboard and capable of accommodating wireless telephones within a cell that is a wireless service area, by monitoring running situations of a plurality of the wireless base stations by the switchboard to compare it with a base station status pattern table stored in the switchboard, to give an instruction for a radio wave radiation characteristic, transmission power and a receiving sensitivity of each wireless base station responding to this comparison result, thereby to automatically control a cell configuration of the wireless base station responding to the operational situation of the system, and to eliminate occurrence of a call loss.
Utilizing the technology disclosed in the foregoing patent document 1 causes the following problems to occur. At first, only if all terminals within the wireless LAN system corresponded to the load balancing control of the above technology, the above technology works effectively. That is, a necessity occurs for adding to the inside of all terminals a function of performing a process according to a request for connection to other AP. Thus, causing the above control to work necessitates that each terminal under the system be a terminal that corresponds to the above control, which is not only costly, but also inconvenient in that the conventional appliances are impossible to use.
Also, it is considered that the load in the wireless LAN system, which depends upon a utilizing method of each location within the area, a layout of utensils, etc., becomes high routinely in the area in which many users exist routinely. In the load balancing control technique as disclosed in the patent document 1, the load is monitored and controlled in real time, whereby the load balancing control is frequently taken in the area in which the load is high routinely. In this control technique, the control is frequently taken because peculiar control messages are exchanged between the AP and each of the terminals, which causes an amount of this control messages to be increased and incurs a decline in performance. Also, it can be thought that the high load status of each AP can be essentially removed by increasing the installation position of the AP or the number of the installed AP for the area in which the load is high routinely, responding to a deviation of the users that depended upon a utilizing method of the above area, the layout of the utensils, etc.; however as a matter of fact, it is impossible to do so with the method as disclosed in the patent document 1.
Further, there is a case of coming into the overload situation when the load that occurred in each terminal is high even though the terminal number is small because the load is assumed to be proportional to the terminal number.
In the technology of the foregoing patent document 2 was not disclosed a concrete realization example for taking a alteration control of the cell configuration of each wireless base station, whereby the problem exists that it is entirely unclear whether an alteration to the really-targeted cell configuration is possible.